1. Field of the Invention
The present invention generally relates to an image processing apparatus for processing a code sequence compressing an image.
2. Description of the Related Art
The following technologies for transmitting image data are known as conventional technologies. Japanese Laid-Open Patent No. 2000-101537 discloses a technology in that an image is divided into several layers and an image quality is controlled based on a status of a network.
Japanese Laid-Open Patent No. 2001-274861 discloses another technology in that in a transmission of dynamic image data, a data frame is transmitted again when a priority of the data frame, which is dropped, of the dynamic image data received is higher than a threshold.
As an image compression technology capable of easily processing a high definition image, the JPEG 2000 is standardized.
There is a data structure of the code sequence in that when the occurrence of an error is detected in a code sequence while transmitting the code sequence compressing the image, only a code part where the error occurred in the code sequence is deleted and the image is decoded by using the code other than the code part, so that that decoded image having its own image quality can be obtained.
The JPEG 2000 recently standardized has this feature, and the code data are structured by a plurality of code units called packets. Even if an error occurs to one packet and this packed is deleted, all packets other than this packet are decoded so as to decode and restructure the entire image.
However, in a case in that several errors occur to the code sequence, or depending on a location of an error, even if the image is decoded by using the packets in which other errors do not occur, the image quality is significantly degraded and contents of the image cannot be recognized. In this case, the conventional technologies cannot determine whether or not the image decoded by using the packets other than error packets is economical, or whether or not the code sequence is needed to be provided again if it is determined that image decoded by using the packets other than error packets is not economical for use. Accordingly, it is inconvenience for a user.